383840021 has 4 divisors (see below), whose sum is σ = 386601600. Its totient is φ = 381078444.

The previous prime is 383839979. The next prime is 383840053. The reversal of 383840021 is 120048383.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 383840021 - 2¹⁰ = 383838997 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (383840081) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1380581 + ... + 1380858.

It is an arithmetic number, because the mean of its divisors is an integer number (96650400).

Almost surely, 2^383840021 is an apocalyptic number.

It is an amenable number.

383840021 is a deficient number, since it is larger than the sum of its proper divisors (2761579).

383840021 is a wasteful number, since it uses less digits than its factorization.

383840021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2761578.

The product of its (nonzero) digits is 4608, while the sum is 29.

The square root of 383840021 is about 19591.8355699511. The cubic root of 383840021 is about 726.7472852181.

The spelling of 383840021 in words is "three hundred eighty-three million, eight hundred forty thousand, twenty-one".